The current developments of wireless local area network (WLAN) interworking with general packet radio service/universal mobile telecommunications system/third generation (GPRS/UMTS/3G) networks has resulted in products that include two radio units in a common enclosure (e.g., cards supporting 802.11b+GPRS air interfaces and 802.11b+UMTS air interfaces). The units may be separate cards or may be integrated onto one common card.
Hereafter a wireless transmit/receive unit (WTRU) includes but is not limited to a user equipment, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, a base station includes but is not limited to a Node-B, site controller, access point or any other type of interfacing device in a wireless environment.
Currently the network may not be aware of the dual-mode capabilities of the terminal. In addition, the offered services may change dramatically based on the terminal capabilities in terms of processing power, memory availability, screen size, bit rate, etc. For example, a dual mode 802+GPRS personal digital assistant (PDA) may be able to receive short message service (SMS) or multimedia message service (MMS) messages over a GPRS or an 802 network, however, several variations of these services may be provided in accordance with allotted memory space of the wireless terminal. Rich multimedia services may require larger memory size than that available in the PDA. Therefore, the same multimedia services may be provided via black and white or a reduced set of colors depending on terminal capabilities. Also, the possibility of network-assisted handoff can be provided to those terminals that indicate dual mode (WLAN/GPRS or WLAN/3G) capabilities. A mechanism is needed to indicate these capabilities to the existing GPRS/UMTS networks.
In addition, in network interworking, there is no capability of informing a wireless terminal having dual-mode radio capabilities and relying upon one of the networks with which it communicates to be advised of the interworking capability to enable the wireless terminal to have the increased ability of communicating with either of the two networks.